JP3715293B2 - Method of forming a screw having a locking function and a plastic working tool for forming the screw - Google Patents

Description

  The present invention relates to a method of forming a screw having a locking function and a plastic working tool for forming (scumming up) the screw, and more particularly to a tapping tap.

  As shown in FIG. 10, a raised tap, which is a kind of plastic working tool for threading, generally includes a threaded portion 2 having a tapered biting portion 3 (not shown) and a parallel threaded portion 4 continuous therewith. The conventional thread of the raised tap 1 has both flank surfaces that are straight from the thread crest 5 of the outer diameter d to the vicinity of the valley bottom 6 in accordance with a regular thread angle (flank angle) according to the thread standard. (Flanks) 7 and 8, and the flank tap 1 by both flank surfaces 7 and 8, as shown in FIG. 11, when screwed into the lower hole 12 of the female thread material 11, the inner peripheral surface of the lower hole 12 is A female screw 16 having a thread 15 having both flank surfaces 13 and 14 of a regular thread angle according to the thread standard, which is pressed and raised while bringing the two ridges into a single thread form. Form.

On the other hand, as a conventional screw member having a locking function, a bolt or a nut provided with a portion where the thread angle is changed to prevent the locking is provided near the outer diameter of the bolt or the inner diameter of the nut (near the top of the thread). It is known from Patent Document 1.
JP 2002-106539 A (Japanese Patent Application No. 2000-302726)

  However, in the conventional screw having the locking function, the position for changing the thread angle (flank angle) is not clear, so that the locking function cannot be exhibited reliably, and a method for machining the thread has been established. There was also a problem that it was difficult to process.

  In addition, there is a problem that it is difficult to insert the male screw into the female screw and screw it into the female screw due to the interference between the female screw and the male screw at the thread angle change portion provided from the screw end portion for preventing the loosening.

  By the way, according to the research of the present inventor, when forming a female screw with a raised tap, generally, the two ridges that rise from the vicinity of the effective diameter of the female screw to the top of the screw thread are brought close to each other so that both flank surfaces of the screw thread are It has been found that these ridges can be elastically deformed in a direction approaching each other if they are not too close during the embossing process.

  This invention is based on the above circumstances and was made in view of the above-mentioned knowledge of the inventor of the present application. When forming a screw, the above-mentioned protrusion on the way from the vicinity of the bottom of the flank of the thread to the summit A screw with a loosening prevention function that is formed so that it can be elastically deformed by being pushed by the flank surface of the screw of the screwing partner by changing the thread angle (flank angle) from the position where it hangs to the top of the mountain Forming method and a plastic working tool for forming the screw, in particular, a raised tap, a screw forming method having a locking function and easily screwed with a screw to be screwed, and a raised tap for forming the screw It is for the purpose.

  According to a first aspect of the present invention, there is provided a method for forming a screw having a locking function according to the present invention, wherein a screw material is pressed by a tool thread of a plastic working tool to raise two ridges. While moving toward the thread of the book, at least one of the ridges is positioned at the effective diameter position of the flank surface on at least one side of the tool thread and the lower allowable limit of the thread to be machined that fits the tool thread. By forming a screw thread by escaping to the relief part between the thread angle change position between the position corresponding to the peak and the vicinity of the valley bottom, the ridge forming the flank surface on at least one side of the thread A portion where the screw thread angle is smaller than the normal angle is formed from the screw thread angle changing position closer to the screw thread top than the effective diameter to the vicinity of the screw thread top.

  According to a fourth aspect of the present invention, there is provided a plastic working tool for forming a screw having a locking function according to the present invention, wherein the screw material is pressed by a tool screw thread to raise two ridges. In a plastic working tool that forms a screw by approaching the shape of a screw thread, on the flank surface of at least one side of the tool thread thread, the lower permissible limit of the effective diameter position and the work thread that fits the tool thread thread A relief portion having a screw thread angle smaller than a normal angle is provided from the position of changing the screw thread angle to the position corresponding to the top of the thread to the vicinity of the valley bottom.

  Further, according to the fifth aspect of the present invention, there is provided a raised tap for forming a female screw having a locking function according to the present invention, wherein a threaded portion having a tapered bite portion and a parallel thread portion continuous therewith is provided. And at least one flank surface of the threaded portion includes a relief portion having a thread angle smaller than a normal angle from a thread angle changing position between the effective diameter and the maximum allowable inner diameter of the female thread to the vicinity of the valley bottom. It will be.

  In the method of forming the screw having the locking function of the present invention, while pressing the screw material with the tool thread of the plastic working tool to raise the two ridges and bring it into a single thread shape, At least one of the ridges is located between the effective diameter position of the flank surface on at least one side of the tool thread and the position corresponding to the peak of the lower allowable limit of the work screw that fits the tool thread. By escaping to the relief part extending from the thread angle change position to the vicinity of the valley bottom to form a thread, the ridge forming the flank surface on at least one side of the thread has a position of effective diameter or more than that. Since the thread angle is smaller than the normal angle from the thread angle change position near the screw peak to the vicinity of the screw peak, the above thread angle of the screw formed on the screw material by this method is the normal angle. Than Small portions, since reliably elastically deformable since it is formed on the summit nearer raised base of the ridge from the effective diameter around, is pressed by flank surfaces of the engagement partner thread is elastically deformed. In addition, according to the method of the present invention, the thread angle change position is set between the effective diameter position and the position corresponding to the lower allowable peak of the work screw fitted to the tool thread. Therefore, a portion where the thread angle is smaller than the normal angle is surely formed on the ridge forming the thread.

  Therefore, according to the method for forming a screw having the locking function of the present invention, a screw that reliably exhibits the locking function can be formed. In addition, the portion from the bottom of the valley of the flank surface of the formed screw to the position of the effective diameter or the thread angle change position closer to the top of the thread becomes the normal thread angle, and is screwed closely with the screw of the screwing partner. Therefore, it is possible to form a screw having a locking function and a sufficiently large fastening force. Moreover, since the screw is formed by plastic processing, it is possible to easily and inexpensively process a screw having a locking function, and since it is not a cutting process, the processing location is not contaminated by chips, and a fine part can be cut. Since it is not necessary, the life of the machining tool can be extended.

  On the other hand, in the plastic working tool for forming a screw having a locking function according to the present invention, the screw material is pressed with the tool screw thread to raise the two ridges and bring it into one screw thread shape. The thread between the effective diameter position and the position corresponding to the peak of the lower allowable limit of the machined screw that fits into the tool thread on the flank surface of the tool thread at least on one side of the tool thread An effective diameter is provided on the ridge that forms a flank surface on at least one side of the thread to be formed at a relief portion that is provided between the angle change position and the vicinity of the valley bottom and whose thread angle is smaller than a normal angle. A portion where the screw thread angle is smaller than the normal angle is formed from the position of the screw thread angle or the screw thread angle changing position closer to the screw thread top to the vicinity of the screw thread top.

  Therefore, according to the plastic working tool for forming a screw having the locking function according to the present invention, the screw forming method having the locking function according to the present invention described above is used to form a screw having the locking function. Therefore, it is possible to form a screw that reliably exhibits the locking function, and it is possible to form a screw that has a locking function and a sufficiently large fastening force. In addition, a screw having a locking function can be processed easily and inexpensively, the processing place is not contaminated by chips, and the life of the processing tool can be extended.

  Then, according to the female tap forming tap having the locking function of the present invention, the above-described screw forming method having the locking function of the present invention is used to form the female screw having the locking function. Therefore, it is possible to reliably prevent the formed female screw from being loosened, and it is possible to form a female screw having a sufficiently large fastening force at the same time as having a locking function. Moreover, since the female screw is provided with a function to prevent loosening while forming the female screw not by cutting but by forming the female screw, the machining location is not contaminated by chips, and the fine portion is not cut. The service life of the tap to be processed can be extended.

  In the method of forming a screw having a locking function according to the present invention, a portion where the thread angle is smaller than a regular angle may be formed at a position away from the end of the screw. If this is the case, the female screw and the male screw begin to interfere with each other at a portion where the screw thread angle is smaller than the normal angle, and thus the male screw can be easily inserted into the female screw. it can.

  In the method of forming a screw having a locking function according to the present invention, a portion of the screw on which the screw thread angle is smaller than a normal angle is applied to the side on which the screw tightening force of the screw is engaged. It is also possible to form it only on the flank surface, and in this way, the part where the thread angle is smaller than the regular angle is formed only on one flank surface, but the loosening prevention action is somewhat reduced. The male screw can be easily screwed into the female screw.

  On the other hand, in the raised tap for forming an internal thread having a locking function according to the present invention, the relief part may be provided in a portion in the biting part direction from the middle of the screw part. Since the female screw and the male screw begin to interfere with each other by the part where the screw thread angle formed by the relief part is smaller than the normal angle, the male screw is easily inserted into the female screw and screwed together. be able to.

  Further, in the female thread forming tap having a locking function according to the present invention, the flank on the side on which the tightening force of the male screw engaged with the female screw of the female screw formed by the rising tap acts as the relief portion. It may be provided only on the flank surface on the side where the surface is processed, and in this way, at the relief portion, the part where the thread angle is smaller than the normal angle is formed only on one flank surface, Although the locking action is somewhat reduced, the male screw can be easily screwed into the female screw.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows the formation of a screw having a locking function according to the present invention, which is used in the method of forming a female screw having a locking function as a first embodiment of the method of forming a screw having a locking function according to the present invention. FIG. 2 is a side view showing the overall shape of a raised tap as a first embodiment of a raised tap for forming a plastic threading tool and a female thread forming tap having the function of preventing loosening according to the present invention. FIG. 2 shows the locking function of the first embodiment. FIG. 3 is an enlarged cross-sectional view showing the parallel thread portion of the threaded portion of the raised tap for forming an internal thread, and FIG. 3 shows the first embodiment using the raised tap for forming an internal thread having a locking function of the first embodiment. FIG. 4 is a cross-sectional view showing a state of female screw formation by a method of forming a female screw having a locking function according to one embodiment, and FIG. 4 is a diagram showing a female screw formed by the method of forming a female screw having a locking function according to the first embodiment. Is Sectional view showing, in comparison with the external thread, and Figure 5 is a sectional view showing a state in which the there male screw the internal thread formed by the method of forming the female screw having a locking function of the first embodiment are screwed together.

  As shown in FIG. 1, a female tap forming tap 1 having a locking function according to the first embodiment includes a tapered biting portion 3 and a parallel screw portion 4 continuous therewith. As shown in FIG. 2, the position of the effective diameter d2 and the position of the female screw inner diameter allowable maximum value D1m are formed on both flank surfaces 7 and 8 of the thread (tool thread) over the entire length of the threaded portion 2. (The position corresponding to the peak of the lower allowable limit of the work screw fitted to the tool thread) An escape portion 9 having an angle smaller than the normal angle on the screw standard is provided, so that the cross-sectional shape of both flank surfaces 7 and 8 of the screw thread of the screw part 2 is effective from the screw thread top 5 of the outer diameter d. Thread angle located at d2 or closer to valley bottom 6 Up to the further position CP, a straight line is formed at a regular thread angle, but at the relief part 9 near the valley bottom 6 from the thread angle change position CP, the thread angle is smaller than the regular angle (tap center axis line). C).

  In the female thread forming method of the first embodiment in which the female thread is formed using the raised tap 1 of the first embodiment, as shown in FIG. From the vicinity of the effective diameter D2 by screwing the raised tap 1 and pressing the inner peripheral surface of the prepared hole of the female thread material 11 with the biting portion 3 and the parallel screw portion 4 of the threaded portion 2 of the raised tap 1 of the first embodiment. While raising the two ridges and bringing the ridges into a single screw thread to form the female screw 16, the two ridges are placed on the relief portion 9 of the raised tap 1 of the first embodiment. Accordingly, the effective diameter D2 of the female screw 16 is formed on the two ridges forming the two flank surfaces 13 and 14 of the thread 15 of the female screw 16 so as to be separated from each other as compared with a normal female screw. Thread between the position and the position of the female screw inner diameter allowable maximum value D1m From the angle change position CP to the vicinity of the female thread top, a portion 17 is formed in which the thread angle is smaller than the normal angle (closer to the female screw central axis), so that the thread angle is smaller than the normal angle. Since the small portion 17 is formed from the position at the base of each protrusion or a position closer to the top of the screw thread to the vicinity of the top of the screw thread, it can be reliably elastically deformed. In addition, in this method, the thread angle changing position CP is set between the position of the effective diameter D2 and the position of the female screw inner diameter allowable maximum value D1m corresponding to the peak of the lower allowable limit of the female screw. Therefore, the portion 17 whose thread angle is smaller than the normal angle is surely formed on the two protrusions forming the thread 15 of the female thread 16.

  As shown in FIG. 4, the portion 17 in which the screw thread angle is smaller than the normal angle is apparent when compared with the male screw 21 screwed into the female screw 16, the screw thread 22 of the male screw 21. The angle of the flank surfaces 23 and 24 of the normal angle interferes with the portion near the valley bottom 25, but from the base of each protrusion by a distance α (α ≧ 0) from the position near the top of the screw thread. Is formed. Therefore, as shown in FIG. 5, when the male screw 21 is screwed into the female screw 16, the portions of the flank surfaces 23, 24 of the normal thread angle of the thread 22 of the male screw 21 near the valley bottom 25 are The flank surface of the part 17 of the female screw 16 having a screw thread angle smaller than the normal angle is pushed and the part is elastically deformed so that the parts 17 come close to each other, whereby both flank surfaces 23 and 24 of the male screw 21 are formed. Further, the two portions 17 of the female thread 16 are firmly pressed by the repulsive force due to the elastic deformation, so that the loosening prevention action is surely exhibited.

  Therefore, according to the method for forming the female screw having the locking function of the first embodiment, the female screw 16 that reliably exhibits the locking function can be formed. Further, the portion from the vicinity of the valley bottoms of the flank surfaces 13 and 14 of the formed female screw 16 to the position of the effective diameter or the screw thread angle changing position CP closer to the summit than that becomes the normal screw thread angle. Since the screws are closely screwed together, it is possible to form the female screw 16 having a locking function and a sufficiently large fastening force. In addition, since the internal thread 16 is formed by plastic processing, the internal thread 16 having a locking function can be processed easily and inexpensively, and since it is not a cutting process, the processing location is not contaminated by chips, and a fine portion is not formed. Since cutting is not required, the life of the build-up tap 1 can be extended.

  Then, according to the female thread forming tap 1 having the locking function of the first embodiment, the lifting process is performed by the above-described method of forming the female screw having the locking function of the first embodiment. Since the female screw 16 having the above-described structure can be formed, the same effects as those of the method for forming the female screw having the locking function of the first embodiment described above can be provided.

  FIG. 6 shows a plastic working for forming a screw having a locking function according to the present invention, which is used in a method for forming a female screw having a locking function as a second embodiment of the method for forming a screw having a locking function according to the present invention. Sectional drawing which expands and shows the parallel thread part among the thread parts of the build-up tap as 2nd Example of the build-up tap for the formation of a tool and the internal thread of this invention which has a locking function of this invention, FIG. 7 is said 2nd implementation. Sectional drawing which shows the female screw formed by the formation method of the female screw with a loosening prevention function of the said 2nd Example using the raising tap for female screw formation with an example of a loosening prevention function in contrast with the male screw screwed there It is.

  As shown in FIG. 6, the raised tap 1 for forming a female screw having a locking function of the second embodiment has a relief portion 9 having a screw thread angle smaller than a normal angle, within the entire length of the screw portion 2. Only the point provided in the portion in the direction of the biting portion 3 including the biting portion 3 from the middle of the parallel screw portion 4 is different from the first embodiment, and the other portions are the same as those of the first embodiment. It is constituted similarly.

  According to the raised tap 1 for forming the female screw having the locking function of the second embodiment and the method for forming the female screw having the locking function of the second embodiment using the same, the rising tap of the first embodiment is used. As shown in FIG. 7, two protrusions that form both flank surfaces of the screw thread 15 are provided in the vicinity of the inlet of the female screw 16 as well as the same effect as the method of forming the female screw 1 and the female screw using the same. The female screw 16 and the male screw 21 begin to interfere with each other by the portion 17 in which the thread is a protrusion 18 having a regular thread angle and the thread angle formed by the relief portion 9 is smaller than the regular angle. Since it is behind the vicinity of the entrance, the female screw 16 can be easily inserted and screwed into the male screw 21.

  FIG. 8 shows a plastic working for forming a screw having a locking function according to the present invention, which is used in a method for forming a female screw having a locking function as a third embodiment of the method for forming a screw having a locking function according to the present invention. Sectional drawing which expands and shows the parallel thread part of the thread part of the build-up tap as 3rd Example of the build-up tap for the formation of a tool and the internal thread of this invention which has a locking function of this invention, FIG. 9 is said 3rd implementation. Sectional drawing which shows the female screw formed by the formation method of the female screw with a locking function of the said 3rd Example using the riser tap for female thread formation of an example of a locking function as compared with the male screw screwed there It is.

  As shown in FIG. 8, the raised tap 1 for forming a female screw having a locking function according to the third embodiment has a female thread in which a relief portion 9 having a screw thread angle smaller than a regular angle is formed by the raised tap 1. 16, only the flank surface 8 on the side on which the flank surface (flank surface 13 of the female screw 16 in FIG. 9) on which the tightening force of the male screw 21 engaged with the female screw 16 acts is provided. It is different from the previous first embodiment, and other parts are configured in the same manner as the first embodiment.

  According to the raised tap 1 for forming the female screw having the locking function of the third embodiment and the method for forming the female screw having the locking function of the third embodiment using the same, the rising tap of the previous first embodiment is used. 1 and an effect similar to that of the female screw forming method using the same, as shown in FIG. 9, the relief portion 9 has a portion 17 having a screw thread angle smaller than a regular angle on one side. Is formed only on the flank surface 13 and the other flank surface 14 is a ridge 18 having a regular thread angle, so that the loosening prevention action is somewhat reduced, but the female screw 16 and the male screw 21 can be easily screwed together. Can be

  Although the present invention has been described based on the illustrated examples, the present invention is not limited to the above-described example. For example, the plastic working tool for forming a screw having a locking function according to the present invention has the relief portion on the tool thread. A rolling die for forming a male screw having a locking function by rolling may be used, and the method of forming a screw having the locking function of the present invention using the rolling die is used as a tool screw. It may be plastically processed with a rolling die having the escape portion in the mountain.

  Thus, according to the method for forming a screw having a locking function of the present invention and the plastic working tool for forming a screw having the locking function of the present invention, a screw that reliably exhibits the locking function can be formed. In addition, it is possible to form a screw having a locking function and a sufficiently large fastening force. In addition, a screw having a locking function can be processed easily and inexpensively, and the processing location is not contaminated by chips, and the life of the processing tool can be extended.

A plastic working tool for forming a screw having a locking function according to the present invention, which is used in a method for forming a female screw having a locking function, as a first embodiment of the method for forming a screw having a locking function according to the present invention, and the present invention It is a side view which shows the whole shape of the rising tap as 1st Example of the rising tap for formation of the internal thread which has a loosening prevention function. It is sectional drawing which expands and shows the parallel thread part of the thread parts of the build-up tap for female thread formation with the locking function of the said 1st Example. It is sectional drawing which shows the internal thread formation state by the formation method of the internal thread with the loosening prevention function of the said 1st Example using the raising tap for formation of the internal thread with the locking function of the said 1st Example. It is sectional drawing which shows the internal thread formed by the formation method of the internal thread with a locking function of the said 1st Example as contrasted with the external thread screwed there. It is sectional drawing which shows the internal thread formed by the formation method of the internal thread with the locking function of the said 1st Example in which the external thread was screwed there. A plastic working tool for forming a screw having a locking function according to the present invention, which is used in a method for forming a female screw having a locking function, as a second embodiment of the method for forming a screw having a locking function according to the present invention, and the present invention It is sectional drawing which expands and shows the parallel thread part among the thread parts of the build-up tap as 2nd Example of the build-up tap for female thread formation which has a loosening prevention function. The female screw formed by the method of forming the female screw having the locking function of the second embodiment using the raised tap for forming the female screw having the locking function of the second embodiment is compared with the male screw screwed therein. FIG. A plastic working tool for forming a screw having a locking function according to the present invention, which is used in a method for forming a female thread having a locking function, as a third embodiment of the method for forming a screw having a locking function according to the present invention, and the present invention It is sectional drawing which expands and shows the parallel thread part among the thread parts of the build-up tap as a 3rd Example of the build-up tap for female thread formation which has a loosening prevention function. The female screw formed by the method of forming the female screw having the locking function of the third embodiment using the raised tap for forming the female screw having the locking function of the third embodiment is compared with the male screw screwed therein. FIG. It is sectional drawing which illustrates the raising tap which is a kind of the conventional plastic working tool for screw machining. It is sectional drawing which shows the internal thread formation state by the said conventional heightening tap.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Raise tap 2 Thread part 3 Chamfer part 4 Parallel thread part 5 Screw crest 6 Valley bottom 7,8 (Tap) flank surface 9 Relief part 11 Female thread material 12 Pilot hole 13, 14 (Female thread) Flank surface 15 (Female thread ) Thread 16 Female thread 17 Portion where the thread angle is smaller than the regular angle 18 (Screw thread) Projection of regular thread angle 21 Male thread 22 (Male thread) Thread 23, 24 (Male thread) Frank Face 25 (Male thread) Valley bottom C Tap center axis d (Tap) outer diameter CP Thread angle change position d2 (Tap) effective diameter D1m Female thread inner diameter allowable maximum D2 (Female thread) effective diameter α Thread angle change position Distance from the base of the ridge

Claims (7)

  While pressing the screw material with the tool thread of the plastic working tool to raise the two ridges and bring them into a single thread shape, at least one of the ridges is a flank on at least one side of the tool thread. Relief to the relief part between the thread angle change position between the effective diameter position of the surface and the position corresponding to the peak of the lower allowable limit of the work screw fitted to the tool thread, to the vicinity of the valley bottom By forming the screw thread, the thread angle is more than the normal angle from the thread angle change position closer to the top of the thread than the effective diameter to the ridge that forms the flank surface of at least one side of the thread. A method for forming a screw having a locking function, characterized in that a small portion is formed.   2. The method for forming a screw having a locking function according to claim 1, wherein a portion where the screw thread angle is smaller than a normal angle is formed at a position away from an end portion of the screw.   The portion where the screw thread angle is smaller than a normal angle is formed only on the flank surface of the screw on the side on which the tightening force of the screw screwed to the screw acts. 2. A method of forming a screw having a locking function according to 2. In a plastic working tool that presses a screw material with a tool screw thread to raise two ridges and closes it to one screw thread to form a screw,
The at least one flank surface of the tool screw thread has a root from a thread angle change position between an effective diameter position and a position corresponding to the lower allowable peak of the work screw fitted to the tool screw thread. A plastic working tool for forming a screw having a locking function, wherein a relief portion having a screw thread angle smaller than a normal angle is provided over the vicinity. In a rising tap (1) comprising a threaded portion (2) having a tapered bite portion (3) and a parallel threaded portion (4) continuous thereto,
From the thread angle change position (A) between the effective diameter (d) and the female thread inner diameter allowable maximum value (D1m) to the flanks (6) near the flanks (7, 8) on at least one side of the thread portion A raised tap for forming an internal thread having a locking function, wherein a relief portion (9) having a screw thread angle smaller than a regular angle is provided.   6. The internal thread having a locking function according to claim 5, wherein the relief portion (8) is provided in a portion in the direction of the biting portion (5) from the middle of the screw portion (4). Raise tap.   The flank on the side of machining the flank surface (13) on the side where the tightening force of the male screw (21) screwed into the female screw (16) of the female screw (16) that forms the relief portion (9) with the raised tap is applied. 7. A raised tap for forming an internal thread having a locking function according to claim 5 or 6, characterized in that the tap is provided only on the surface (8).

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